Automatic safety stopping device for elevators.



A. FULLER. AUTOMAHC SAFETY STOPPING DEVICE FOR ELEVATORS.

APPLICATION FILED APR- 3. 1914.

1,148,450. Patented July 27, 1915.

ammo 0 COLUMBIA PLANCGRAPH C D WASHINGTON, n c.

UNITED STATES PATENT OFFICE.

ALLEN A. FULLER, OF BIRMINGHAM, ALABAMA, ASSIGNOR OF ONE-HALF TO 0. M.

MCCRUM, OF BIRMINGHAM, ALABAMA.

AUTOMATIC SAFETY STOPPING DEVICE FOR ELEVATORS.

Specification of Letters Patent.

Patented July 27, 1915.

Application filed April 3, 1914. Serial No. 829,381.

To all whom it may concern:

Be it known that I, ALLEN A. FULLER, a citizen of the United States ofAmerica, residing at Birmingham, in the county of Jefferson and State ofAlabama, have invented certain new and useful Improvementsin AutomaticSafety Stopping Devices for Elevators, of which the following is aspecification. 1

My invention relates to safety appliances for elevators and its objectis to utilize any relative movement that may take place from any causebetween the elevator car and its governor cableto eflect a quickapplication of brakes to stop the car without the emergency clamp on thecar being brought into service.

I have found in practice that the governor cable becomes blocked in itstravel with the car from various causes, such as where a broken strandof the cable catches in the openings in the pent house floor; where ragsor like matters are caught in the pit sheave for the governor cable; orwhere the cable jumps the governor sheave. In any of these events theclevis on the governor cable is jerked loose from the cable clamp on thetop of thecar and proceeds to pull on a cable which leads to the drum onthe bottom of the car and unwind-s it to apply the emergency clamps.

According to my invention, as soon as the governor cable is blocked forany reason, or breaks, its resulting movement, relative to the caractuates means which cause the application of brakes which act on thecar hoisting means in ample time to stop the car before the emergencyclamps under the car go into operation.

My invention also comprises the details of construction and arrangementof parts which are illustrated in their preferred embodiment only in theaccompanying draw ings, and which are hereinafter moreparticularlydescribed and claimed, in which Figure 1 is avertica'lsectional elevation of a car looking toward the front. Fig. 2 is adiagrammatic view showing in part the circuit connections controlled bymy automatic switch which is shown in plan view. Fig. 3 is a verticalsectional view through the switch casing showing the switch in itsseveral operating positions.

Similar reference numerals refer to similar parts throughout thedrawings.

Referring to the preferred embodiment of my invention illustrated in theaccompanymg drawings, I show an elevator 1, connected to hoist cables 2,and guided as it is raised and lowered in its shaft by side rails 3. Thecar is provided with the usual form of clutch 1 which frictionallyengages a clevis 5 connected to the endless governor cable 6. A slackcable 7 is also attached at one end to the clevis and its other end ispassed around pulleys in a bearing frame 8, fast to the cross beam 9 atthe top of the elevator, and around a pulley 10 at the bottom of the carand connected to the drum 10 of the usual emergency clamp mechanism.This cable is adapted to act in the well known manner to turn the drumand force the emergency clamp mechanism to engage the guide rails 3 andstop the car. The governor cable 6, by means of the clutch 4 is causedto travel with the car and in doing so it passes around a sheave 11 inthe pent house and over a sheave 12 in the pit. The sheave 11, as it isturned by the governor cable, acts through suitable connections to drivea governor 13 adapted, in the well understood manner, to apply thebrakes and stop the car under excessive speed conditions. The car may beequipped with any suitable control mechanism such as the car switch 14and the emergency switch 15.

I have illustrated in Fig. 2 diagrammatically a part of a standardarrangement of circuit connections and control mechanism now commonly inuse but it will be understood that such arrangement forms no part of mypresent invention and may be widely varied in accordance with theconditions of and re quirements for each installation. In thearrangemen-t illustrated, the supply mains lead to the points 16 and 17for the circuit breaker switch 18. From one leg of this switch thepositive wire 19 leads to general control mechanism, not shown, and hasa branch 20 leading through switches normally closed but which arecontrolled by the governor 13 and the limit switch magnets 21, to themagnet 22 which, when energized, holds the circuit breaker switch 18 inclosed position. The wire 20 continues to the emergency switch 15 andthere branches, one leg 23 leading to the negative main 24 and the otherleg 25 to the car switch 14 from which the various circuit wires lead tothe control mechanism. The armature 26 of the motor which moves thehoist cables, has a coil 27 thereof connected in a circuit 28 normallyopen circuited at the contacts 29 which are arranged to be closed by thecircuit breaker switch 18 when the latter opens responsive to thedenergizing of the coil 22 by the opening of either limit switch 21 orthe governor controlled switch 13, or the emergency switch 15 on thecar. When the circuit 28 is closed thearmature 26 is short circuited andacts as a magnetic brake in conjunction with the other brakes to quicklystop the car.

My automatic safety stop switch is preferably .interposed in the circuit20 in which the magnet 22 and both car switches 1=l and 15 are included,and comprises an insulated base 30 having spaced contacts 31 thereonadapted to receive between them a knife switch 32. The switch. 32 ismounted on a shaft 33 which turns in suitable bearings 3%- which arepreferably disposed in a boX or casing 35 that is attached to theelevator car at any suitable point, preferably within the car oppositethe governor cable. The shaft 33 projects without the boX and carries onits outer end a crank arm 36 bifurcated at its end to form spaced arms37 which straddle one side of the endless governor cable. I make fast onthe cable clamps 38 and 39 which are disposed closely together, oneabove and the other below the arms 37. The arrangement of parts is suchthat any relative movement between the car and the cable 6, which isgreater in amount than the play allowed in the detachable connectionbetween the clutch a and clevis 5,

will cause one or the other of the clamps 38 and 39 to engage the crank36 and turn it to swing the knife switch 32 from position between thecontacts 31, thereby opening the circuit 20 both -to the circuit breakercoil 22 and both car switches, thereby causing the immediate applicationof all brake means which act through the hoist cables 2 to stop the car.All brake means so acting are what I term the normal brakes, though theyinclude the emergency brake effected by the chort circuiting of thearmature and the resulting conversion of the motor into a brake. Theclamps 3S and 39 are preferably so arranged that in the manner describedthey will effect the stopping of the car before a sufiicient relativemovement shall have taken place between the car and cable 6 to take upthe slack cable 7 and cause the application of the clamps under the car.The clamps will ride past the arms 37 and clear the lever after openingthe knife switch. Also in the event the cable breaks its weight will besuflicient to jerk the knife switch 32 open and apply the emergencybrakes, though under such conditions the clamp mechanism could not beapplied. Further, by my preferred arrangement of the clamps the car isstopped before it accumulates a momentum and in this respect it operatesto minimize the damage both to the car and its guide rails when thegovernor cable becomes blocked or broken. The opening of my automaticstop means has the same effect as the opening of the emergency switch 15and it constitutes in effect a second and automatic emergency switch.This duplication of the emergency switches is adopted solely on thegrounds of convenience of location of the two switches and theadaptation of my invention to elevators now in service.

lVhile it is my desire to have the circuit connections controlled by theopening of my automatic safety switch cause the application of theseveral brake means which normally act on the car hoisting means to stopthe car, yet it will be understood that any one or more of such ordinarybraking means may be thrown into operation by the opening of the safetyswitch and I do not therefore desire to limit myself in respect to thecharacter of the brake controlled by the switch. I regard theconstruction as preferred however in which the braking means will beeffective to arrest the car before the emergency clamps carried by thecar shall have been disturbed or at least sufficiently actuated to gointo service or require resetting.

lVhen I refer to normal brake means I mean merely to distinguish betweensuch means as are now used to act on the hoist means to stop the car andthe emergency stop means which are carried by the car itself and which,when they go into service, are very violent in their action and liableto cause injury or damage.

Obviously, the mechanical means by which relative movement between thecar and the cable is transmitted to operate the switch may be widelyvaried without departing from the spirit of my invention.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is:--

1. The combination with an elevator, hoist means therefor, normal brakemeans which act on the hoist means for the car, emergency brakemechanism carried by the car, a governor cable detachably connected tothe car, an operating connection from said cable to said emergency brakemechanism on the car, electric mechanism for controlling said normalbrake having circuit connections to the car, and a switch in saidcircuit connections, which switch is connected to said cable so as to beopened by any substantial movement thereof relative to the car and applythe normal. brake in advance of any movement imparted by the cable tosaid emergency brake mechanism.

2. Thecombination with an elevator and its hoist and normal brakemechanism, of an emergency mechanical brake attached to the car,electrical means which control the normal brake and comprise acontroller switch on the car, a governor cable, and operatingconnections from said cable to both said switch and said mechanicalbrake, said connections being such as, upon relative movement betweenthe elevator and said cable, to open the switch independently of and inadvance of the operation of said emergency mechanical brake.

3. The combination with an elevator, hoist means therefor, a hoistbrake, a governor cable therefor and normally movable therewith,electrically controlled mechanism for controlling the hoist brake forthe elevator, said mechanism comprising circuit connections and a switchmounted on the car, a lost-motion connection between said switch andgovernor cable for operating the switch by means of said cable when itbreaks or moves bodily in either direction relatively to the car, andmeans controlled by the operation of said switch to apply the hoistbrake.

4. In combination, an elevator car, a governor cable, a switch mountedon said car, means to operate the switch comprising a bifurcated armwhich straddles the governor cable, and lugs on the governor cable aboveand below said arm, said switch being operable by either of said lugswhen relative movement takes place between the car and cable, andelectrical mechanism controlled by said switch for effecting anemergency application of the brakes to the car.

5. The combination with an elevator car and emergency stop mechanismcarried thereby, of a governor cable, means controlled thereby tooperate said emergency stop mechanism, hoist mechanism for the car,brake means acting on said hoist mechanism to stop the car, controlmechanism on the car for releasing and applying said brake means undernormal operating conditions, and means also controlled by said governorcable and adapted to throw said brake means into service independentlyof said emergency stop mechanism and of said normal brake controlmechanism.

6. In combination, an elevator car, a governor cable, a switch mountedon said car, means to operate the switch comprising a switch arm, andmeans on the governor cable adapted to shift said arm in eitherdirection when relative movement takes place between the car and cable,and electrical mechanism controlled by said switch for effecting anemergency application of brakes to the car.

In testimony whereof I aflix my signature in presence of two witnesses.

ALLEN A. FULLER.

Witnesses:

NOMIE WELsH, R. D. JOHNSTON, Jr.

Copies of this patent may he obtained for five cents each, by addressingthe Commissioner of Patentu Washington, D. G.

